Tag Archives: urlwatch

Too Good To, UNIX & Linux

Too good to #0009

1 Comment

In this episode:

  • urlwatch for new daily Ubuntu Server ISO
  • systemd-run ephemeral timers as replacement for at
  • Mozillateam Firefox on Debian
  • systemd service: ExecStartPre as root
  • gdm3 autosuspend/shutdown behaviour

urlwatch for new daily Ubuntu Server ISO

Somewhat desparate because at the time of starting this post, the (pre-beta, non-LTS, not blaming anyone) server image in question was badly broken.

---
name: Ubuntu Server Daily ISO
url: https://cdimage.ubuntu.com/ubuntu-server/daily-live/current/SHA256SUMS
filter:
  - grep: .*-live-server-amd64.iso
---

systemd-run ephemeral timers as replacement for at

Goes great with “hardened” systems that deny use of at(1).

Run a command 60 seconds from now, via the user’s private systemd (after logout only if session lingering is enabled).

systemd-run --user --on-active=60s -- logger --tag foo "Hello world"

Run a command 2 minutes from now, privileged or as a specific user via the global systemd:

sudo systemd-run --uid="${LOGNAME}" --on-active=2m -- touch /tmp/hello

Insights

systemctl --user list-timers
journalctl --user -u 'run-*.timer'
sudo systemctl list-timers
sudo journalctl -u 'run-*.timer'

Mozillateam Firefox on Debian

$ sudo tee /etc/apt/sources.list.d/mozillateam-ppa.list <<Here
deb https://ppa.launchpadcontent.net/mozillateam/ppa/ubuntu jammy main
deb-src https://ppa.launchpadcontent.net/mozillateam/ppa/ubuntu jammy main
Here

$ sudo tee /etc/apt/trusted.gpg.d/mozillateam.asc < <(curl 'https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x0ab215679c571d1c8325275b9bdb3d89ce49ec21')

systemd service: ExecStartPre as root

[Service]
...
User=nonroot
Group=nonroot
ExecStartPre=+install -d /var/lib/theservice -o nonroot -g nonroot
ExecStart=/usr/sbin/theservice

See systemd.service, “special executable prefixes”.

gdm3 autosuspend/shutdown behaviour

Debian:

$ sudo apt-get install dbus-x11
$ sudo chsh -s /bin/bash Debian-gdm
$ sudo -i -u Debian-gdm
$ gsettings get org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type
'suspend'
$ dbus-launch gsettings set org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type nothing
$ gsettings get org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type
$ exit
$ sudo chsh -s /bin/false Debian-gdm

Arch/Garuda:

$ sudo chsh -s /bin/bash gdm
$ gsettings get org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type
'suspend'
$ dbus-launch gsettings set org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type nothing
$ gsettings get org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type
$ exit
$ sudo chsh -s /usr/bin/nologin gdm
Too Good To, UNIX & Linux

Too good to #0002

2 Comments

Show and update the comment in an SSH private key

ssh-keygen -l -f <keyfile> # show
ssh-keygen -c -f <keyfile> # change interactively
ssh-keygen -c -C <newcomment> -f <keyfile> # change and provide new

ssh-agent in Gitlab CI/CD

  • Define SSH_KEY as a “file” in Gitlab CI/CD variables and SSH_PASSPHRASE as a regular variable
  • If libcrypto errors on execution, make sure SSH_KEY has an additional line ending at the end
before_script:
  - DEBIAN_FRONTEND=noninteractive apt-get update -y
  - DEBIAN_FRONTEND=noninteractive apt-get install -y openssh-client

sftp_to_somewhere:
  stage: deploy
  script:
    - chmod 600 "$SSH_KEY"
    - eval $(ssh-agent)
    - ssh-add "$SSH_KEY" <<< "$SSH_PASSPHRASE"
    - ssh-add -l

Urlwatch, but with a local pop-up window on Linux, no additional infrastructure

Systemd user service:

# ~/.config/systemd/user/urlwatch-to-zenity.service
[Unit]
Description=urlwatch to zenity (service)

[Service]
Type=oneshot
ExecCondition=sh -c 'nmcli net co | grep full'
ExecCondition=sh -c 'urlwatch > %h/.cache/urlwatch.out'
ExecCondition=sh -c 'test -s %h/.cache/urlwatch.out'
ExecStart=sh -c 'zenity --title Urlwatch --text-info --width=600 --height=400 --filename=%h/.cache/urlwatch.out'

[Install]
WantedBy=default.target

Systemd timer:

# ~/.config/systemd/user/urlwatch-to-zenity.timer
[Unit]
Description=urlwatch to zenity (timer)

[Timer]
OnStartupSec=1h
OnUnitInactiveSec=2h

[Install]
WantedBy=default.target

cookiecount – Load a page and show the cookies it sets

$ ./cookiecount https://example.com
0 cookies received.

ps1_anon.bash – anonymize bash prompt, for screenshots and pastes

# Anonymize bash prompt for screenshots and pastes
# Source from or add to ~/.bashrc
function ps1_anon (){
	if [[ -v SAVED_PS1 ]] 
	then
		PS1="${SAVED_PS1}" 
		unset SAVED_PS1 
	else
		SAVED_PS1="${PS1}" 
		PS1='\$ '
	fi
}

Example:

[martin@idefix ~/devel/cookiecount(main=)]$ ps1_anon
$ ./cookiecount https://reddit.com --json | jq .cookiecount
7
$ ps1_anon
[martin@idefix ~/devel/cookiecount(main=)]$
Too Good To, UNIX & Linux

Too good to #0001

Set X11 keyboard layout manually and temporarily (e.g. in i3 if I need to test exotic window managers for my users)

setxkbmap -layout us,us -variant altgr-intl -option caps:none

Speaking of which, set keyboard layout permanently in Gnome

gsettings set org.gnome.desktop.input-sources sources "[('xkb', 'us+altgr-intl')]"

Check if Gnome Screensaver is active (I use this for automated time tracking)

busctl --user call org.gnome.ScreenSaver /org/gnome/ScreenSaver org.gnome.ScreenSaver GetActive

Urlwatch for a new package version in an APT repository

After a long wait, I was finally able to find another use for my awful Perl one-liner from 2019 that pivots a Debian Packages.gz into a space-separated table!

---
name: "Pop!OS Firefox package"
command: curl -s http://apt.pop-os.org/release/dists/jammy/main/binary-amd64/Packages.gz |
  gzip -dc | perl -ane 'if($F[0]=~/^Package:/){$p=$F[1]};if($F[0]=~/^Version:/){$v=$F[1];print"$p $v\n";}' |
  grep '^firefox '
diff_filter:
  - grep: '^[+-][^+-]'
---